Truck: 1995 Ford F-150 Centurion 5.8l E4OD
Ok so Just before I bought my house and was getting ready to move my truck took a big giant *****. It started running rough, spitting and sputtering no power after 1/2 throttle unless I ease and I do mean ease on it until it's wide open. While idling it idles around 1100 rpm, where it should be about 600rpm. Also I have a no responsive O/D cancel switch. When I pull the shifter down into Drive it will hardly move almost like its trying to start off in 3rd gear. But if I pull it down to 2nd then I can get somewhere. 1st acts like 2nd does.

I have replaced the TPS, Fuel Pump, Checked for spark, replaced the ignition coil, and replaced the fuel filter. All of which luckily needed some attention anyway. Checked timing and it does not seem to be off. Also the truck will not start when cold without ether. After I start it and let it run for 5 mins I can cut it off and fire it right back up with a hard start.

Forgot to mention that the fuel pump does not prime and cutoff when the key is in the on position. It continues to run. Forgot to mention that the Check engine light is on and I cannot pull codes. Unresponsive.

After much research I'm finding some guys finding their PCM bad. I need a second opinion.

Also which plug on the firewall would be the actual PCM. Theres 2-3 plugs oon the fireway containing quite a few wires in it

 

Forgot to mention that the fuel pump does not prime and cutoff when the key is in the on position. It continues to run. Forgot to mention that the Check engine light is on and I cannot pull codes. Unresponsive.

Both good signs the computer is the problem. Well that and the way it runs too!

Fuel pump continues to run as long as the key is in the run position, rather then run for a second then stop.

MIL is on, can't get codes.

 

Yup, the processor on the computer is not initializing. The lack of ability to pull codes, no O/D Cancel light, the fuel pump constantly priming are signs of this. Without the processor running, the computer also cannot control the transmission. Without computer control, the E4OD's default to 4th gear in "D", and 2nd gear in both "1" and "2".

Ford engineered a "fail safe" into the computer in the event the main processor does not start it up. There's a small secondary chip that's designed to fire the injectors a fixed amount every time it receives a PIP pulse from the distributor. It injects just enough fuel to have enough power to get you home.

It works based on a time-out type of counter. If the main processor is functioning properly, it resets the timer on this secondary chip before it times out. If the processor stops working for whatever reason, it times out and the secondary chip takes over. The fuel pump control is designed the same way. The main processor actually turns it off once it has initialized. That way you should always be able to get home as long as the computer hasn't burnt up inside.

 

+1 to a bad ECM

 

Two views of where the PCM is located:

First


Second


Courtesy of subford

The PCM is removed from the engine side of the firewall.

 

ECM is bad....

Before putting a new computer in your truck, try to find out why your old one failed.

has it:
taken a swim?

had a major accident?
been hit by lighting?
launched a boat at the ramp with the front bumper?


If none of those has happen to your truck, check your wiring. Most computer failures are caused by flood damage, lost of ground, and or over charging of the electrical system.
Not likely but worth saying, water "can" get into the computer just from road splashes if the seal has worn out.

 

I disagree. Most Ford computer failures seemed to be caused by failing capacitors.

 

I agree with the failing capacitors thing especially when it comes to the 5.8. Went to the lkq yard roday to look for a computer. Out of the 12 5.8 trucks and broncos the had out there everyone of them hadvthe pcm missing. Luckily i remembered that some econolines came with the 5.8 E4OD. So i snatched a pcm out of the econoline i found. Slapped it in mine and WALA!!! Happy as a tick in a blood bath.

 

There you go !!!!!!!!
X2

Bob